1. Field of the Invention
The present invention generally relates to a super-pressured high-altitude airship and more specifically, to a high-altitude airship of super-pressure structure which flies in the stratosphere, is propelled against the wind with the power obtained through the photovoltaic conversion of the sunlight, generally allows no in-flow or out-flow of the gas in an airship hull (a gas bag) from or to, respectively, the atmosphere in the stratosphere, is a large-scale LTA (Lighter-Than-Air) platform for observation for the global environmental protections and for telecommunication relay, copes with the temperature fluctuations of the buoyant gas with the pressure resistance, and keeps constant full volume even when the pressure of the buoyant gas if fluctuated.
2. Discussion of Background
Conventional scientific balloons allow expansion of internal helium gas since the balloons do not have air for venting when ascending, and the ascension occurs with an usable buoyancy by preventing a rise in internal pressure rise as compared with the atmospheric air outside of the balloons. In horizontal flight, the balloons are flown by the wind by dropping ballast to cope with the loss of buoyancy. When the balloons have to descend, the balloon skin is ripped in order to vent the buoyant gas, and the payloads descend by parachutes.
On the other hand, in the low stratosphere, namely at an altitude of about 20 km above ground level, the weather is fine throughout the year and the wind is relatively weak, so that it is effective to make a large-scale LTA platform fly in such a space for a long period of time for the purposes of environmental observation and telecommunication relay. In this case, it is difficult to apply a means used for the above-described scientific balloons, but it is necessary to have a propulsion power to keep a position of the platform against the wind in the stratosphere, and at the same time, a means is necessary for ascent and descent of the vehicle which enables high speed shuttling between the stratosphere and the ground.
In such a high-altitude airship, the volumetric increase/decrease caused by the temperature fluctuations, such as the super-heat of the buoyant gas affected by the solar radiation at high altitudes, should be absorbed by air-filled ballonets (i.e., air chambers) allowing air flow from/to the outside atmosphere, which are usually positioned fore and aft of the airship hull, and thereby the trim function of the pitch attitude is provided. For example, if a temperature fluctuation band of the buoyant gas is 70.degree. C., and the mean temperature of the atmospheric air is about -53.degree. C. (220.degree. K in absolute temperature), the ballonet volume of not less than 70/220 of the hull volume is necessary, and as a result, the buoyancy of the ballonet space is lost and a weight is added by ballonet fabric materials, and the gas bag skin of the ballonet forms a free surface of the fluid boundary, namely between ballonet filled air and the buoyant gas in an envelope (airship hull body), which causes problems that the ballonet skin is exposed to the sloshing of the gas, and material fatigue of the fabric is apt to be caused by this kinetic movement.